分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-15
摘要: Insulin resistance and abdominal obesity are present in the majority of people with the metabolic syndrome. Antioxidant therapy might be a useful strategy for type 2 diabetes and other insulin-resistant states. The combination of vitamin C (Vc) and vitamin E has synthetic scavenging effect on free radicals and inhibition effect on lipid peroxidation. However, there are few studies about how to define the best combination of more than three anti-oxidants as it is difficult or impossible to test the anti-oxidant effect of the combination of every concentration of each ingredient experimentally. Here we present a math model, which is based on the classical Hill equation to determine the best combination, called Fixed Dose Combination (FDC), of several natural anti-oxidants, including Vc, green tea polyphenols (GTP) and grape seed extract proanthocyanidin (GSEP). Then we investigated the effects of FDC on oxidative stress, blood glucose and serum lipid levels in cultured 3T3-L1 adipocytes, high fat diet (HFD)-fed rats which serve as obesity model, and KK-ay mice as diabetic model. The level of serum malondialdehyde (MDA) in the treated rats was studied and Hematoxylin-Eosin (HE) staining or Oil red slices of liver and adipose tissue in the rats were examined as well. FDC shows excellent antioxidant and anti-glycation activity by attenuating lipid peroxidation. FDC determined in this investigation can become a potential solution to reduce obesity, to improve insulin sensitivity and be beneficial for the treatment of fat and diabetic patients. It is the first time to use the math model to determine the best ratio of three anti-oxidants, which can save much more time and chemical materials than traditional experimental method. This quantitative method represents a potentially new and useful strategy to screen all possible combinations of many natural anti-oxidants, therefore may help develop novel therapeutics with the potential to ameliorate the worldwide metabolic abnormalities. (C) 2015 The Authors. Published by Elsevier B.V.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-15
摘要: Background: Carcinoembryonic antigen (CEA) is a protein commonly found in human serum, with elevated CEA levels being linked to the progression of a wide range of tumors. It is currently used as a biomarker for malign tumors such as lung cancer and colorectal cancer [Urol Oncol: Semin Orig Invest 352: 644-648, 2013 and Lung Cancer 80: 45-49, 2013]. However, due to its low specificity in clinical applications, CEA can be used for monitoring only, rather than tumor diagnosis. The function of many glycoproteins is critically dependent on their glycosylation pattern, which in turn has the potential to serve in tumor detection. However, little is known about the detailed glycan patterns of CEA. Methods: To determine these patterns, we isolated and purified CEA proteins from human tumor tissues using immunoaffinity chromatography. The glycan patterns of CEA were then analyzed using a Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass Spectrometry3 (MALDI-TOF-MS3) approach. Results: We identified 61 glycoforms in tumor tissue, where CEA is upregulated. These glycosylation entities were identified as bi-antennary, tri-antennary and tetra-antennary structures carrying sialic acid and fucose residues, and include a multitude of glycans previously not reported for CEA. Conclusion: Our findings should facilitate a more precise tumor prediction than currently possible, ultimately resulting in improved tumor diagnosis and treatment.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: With the rapid development of high-throughput sequencing technologies, the emerging of methylated RNA immunoprecipitation sequencing (MeRIP-seq) technology makes it possible to detect RNA epigenetic modifications in a large scale, which allows transcriptome-wide profiling of RNA methylation. Mining the patterns of global mRNA methylation from these MeRIP-seq data can help reveal the potential functional roles of these mRNA methylations in regulating gene expression, splicing, RNA editing and RNA stability, effectively guiding the therapeutic intervention of cancer. Here, the principle of MeRIP-seq sequencing was first introduced. Then, the recent progress of the processing and analysis of MeRIP-seq data were comprehensively discussed. In the end, the computational problems and challenges faced in the process of MeRIP-seq data processing were also summarized.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: With the aim of broadening the versatility of lentiviral vectors as a tool in nucleic acid research, we expanded the genetic code in the propagation of lentiviral vectors for site-specific incorporation of chemical moieties with unique properties. Through systematic exploration of the structure-function relationship of lentiviral VSVg envelope by site-specific mutagenesis and incorporation of residues displaying azide- and diazirine-moieties, the modifiable sites on the vector surface were identified, with most at the PH domain that neither affects the expression of envelope protein nor propagation or infectivity of the progeny virus. Furthermore, via the incorporation of such chemical moieties, a variety of fluorescence probes, ligands, PEG and other functional molecules are conjugated, orthogonally and stoichiometrically, to the lentiviral vector. Using this methodology, a facile platform is established that is useful for tracking virus movement, targeting gene delivery and detecting virus-host interactions. This study may provide a new direction for rational design of lentiviral vectors, with significant impact on both basic research and therapeutic applications.
分类: 生物学 >> 生物物理学 >> 免疫学 提交时间: 2016-05-12
摘要: We previously showed that LIGHT and its receptor herpes virus entry mediator (HVEM) are important for development of optimal CD4(+) Th1 cell immunity and resistance to primary Leishmania major infection in mice. In this study, we further characterized the contributions of this molecule in dendritic cell (DC) maturation, initiation, and maintenance of primary immunity and secondary anti-Leishmania immunity. Flow-cytometric studies showed that CD8 alpha(+) DC subset was mostly affected by HVEM-Ig and lymphotoxin beta receptor-Ig treatment. LIGHT signaling is required at both the priming and the maintenance stages of primary anti-Leishmania immunity but is completely dispensable during secondary immunity in wild type mice. However, LIGHT blockade led to impaired IL-12 and IFN-gamma responses and loss of resistance in healed CD40-deficient mice after L. major challenge. The protective effect of LIGHT was mediated primarily via its interaction with lymphotoxin beta receptor on CD8 alpha(+) DCs. Collectively, our results show that although LIGHT is critical for maintenance of primary Th1 response, it is dispensable during secondary anti-Leishmania immunity in the presence of functional CD40 signaling as seen in wild type mice.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: Tumor-resident proteases (TRPs) are regarded as informative biomarkers for staging cancer progression and evaluating therapeutic efficacy. Currently in the clinic, measurement of TRP is dependent on invasive biopsies, limiting their usefulness as monitoring tools. Here we identified circulating peptides naturally produced by TRPs, and evaluated their potential to monitor the efficacy of anti-tumor treatments. We established a mouse model for ovarian cancer development and treatment by orthotopic implantation of the human drug-resistant ovarian cancer cell line HeyA8-MDR, followed by porous silicon particle-or multistage vector (MSV) -enabled EphA2 siRNA therapy. Immunohistochemistry staining of tumor tissue revealed decreased expression of matrix metallopeptidase 9 (MMP-9) in mice exhibiting positive responses to MSV-EphA2 siRNA treatment. We demonstrated, via an ex vivo proteolysis assay, that C3f peptides can act as substrates of MMP-9, which cleaves C3f at L-1311-L-1312 into two peptides (SSATTFRL and LWENGNLLR). Importantly, we showed that these two C3f-derived fragments detected in serum were primarily generated by tumor-resident, but not blood-circulating, MMP-9. Our results suggested that the presence of the circulating fragments specially derived from the localized cleavage in tumor microenvironment can be used to evaluate therapeutic efficacy of anti-cancer treatment, assessed through a relatively noninvasive and user-friendly proteomics approach.
分类: 生物学 >> 生物物理学 >> 肿瘤学 提交时间: 2016-05-12
摘要: The signal transduction pathway initiated by vascular endothelial growth factor-vascular endothelial growth factor receptor 2 (VEGF-VEGFR2) plays an important role in the angiogenesis of tumors. The effective antagonists of VEGFR2 would behave as potent drugs for the treatment of malignant cancers. In our study, specific binding peptides with high affinity to VEGFR2 were obtained through bacterial display technology. Conserved motif (FF/YEXWGVK) among those peptide sequences was discovered. One of the selected peptides, VRBP1 (YDGNSFYEMWGVKPASES) was identified by screening the biased bacterial peptide library and its physiochemical feature was further characterized. The results of surface plasmon resonance (SPR) assay indicated that the dissociation constant (K-D) value of VRBP1 was 228.3 nM and this peptide competed with VEGF binding to VEGFR2. Particles conjugated with VRBP1 could recognize the human umbilical vein endothelial cells (HUVEC) which express VEGFR2 on the surface. Further therapeutic effect of VRBP1 was examined by in vivo experiments. VRBP1 could result in a significant decrease in tumor size of H460 xenografts. The results from the immunohistochemical assay showed that CD31 positive signals in VRBP1-treated group were fewer than those in the control ones. These data highlighted the potential of VEGFR2-binding peptides as effective molecules for cancer diagnosis and therapy.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: The oxygen-evolving center (OEC) in photosystem II catalyzes a water splitting reaction. Great efforts have already been made to artificially synthesize the OEC, in order to elucidate the structure-function relationship and the mechanism of the reaction. Now, a new synthetic model makes the best mimic yet of the OEC. This recent study opens up the possibility to study the mechanism of photosystem II and photosynthesis in general for applications in renewable energy and synthetic biology.
分类: 生物学 >> 生物物理学 >> 细胞生物学 提交时间: 2016-05-12
摘要: The large dense-core vesicle (LDCV), a type of lysosome-related organelle, is involved in the secretion of hormones and neuropeptides in specialized secretory cells. The granin family is a driving force in LDCV biogenesis, but the machinery for granin sorting to this biogenesis pathway is largely unknown. The mu mutant mouse, which carries a spontaneous null mutation on the Muted gene (also known as Bloc1s5), which encodes a subunit of the biogenesis of lysosome-related organelles complex-1 (BLOC-1), is a mouse model of Hermansky-Pudlak syndrome. Here, we found that LDCVs were enlarged in mu adrenal chromaffin cells. Chromogranin A (CgA, also known as CHGA) was increased in mu adrenals and muted-knockdown cells. The increased CgA in mu mice was likely due a failure to export this molecule out of immature LDCVs, which impairs LDCV maturation and docking. In mu chromaffin cells, the size of readily releasable pool and the vesicle release frequency were reduced. Our studies suggest that the muted protein is involved in the selective export of CgA during the biogenesis of LDCVs.
分类: 生物学 >> 生物物理学 >> 生物力学与生物流变学 提交时间: 2016-05-12
摘要: The human influenza A (H3N2) virus dominated the 2014-2015 winter season in many countries and caused massive morbidity and mortality because of its antigenic variation. So far, very little is known about the antigenic patterns of the recent H3N2 virus. By systematically mapping the antigenic relationships of H3N2 strains isolated since 2010, we discovered that two groups with obvious antigenic divergence, named SW13 (A/Switzerland/9715293/2013-like strains) and HK14 (A/Hong Kong/5738/2014-like strains), co-circulated during the 2014-2015 winter season. HK14 group co-circulated with SW13 in Europe and the United States during this season, while there were few strains of HK14 in mainland China, where SW13 has dominated since 2012. Furthermore, we found that substitutions near the receptor-binding site on hemagglutinin played an important role in the antigenic variation of both the groups. These findings provide a comprehensive understanding of the recent antigenic evolution of H3N2 virus and will aid in the selection of vaccine strains.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: The homeostasis of magnesium (Mg2+), an abundant divalent cation indispensable for many biological processes including mitochondrial functions, is underexplored. Previously, two mitochondrial Mg2+ importers, Mrs2 and Lpe10, were characterized for mitochondrial Mg2+ uptake. We now show that mitochondrial Mg2+ homeostasis is accurately controlled through the combined effects of previously known importers and a novel exporter, Mme1 (mitochondrial magnesium exporter 1). Mme1 belongs to the mitochondrial carrier family and was isolated for its mutation that is able to suppress the mrs2 Delta respiration defect. Deletion of MME1 significantly increased steady-state mitochondrial Mg2+ concentration, while overexpression decreased it. Measurements of Mg2+ exit from proteoliposomes reconstituted with purified Mme1 provided definite evidence for Mme1 as an Mg2+ exporter. Our studies identified, for the first time, a mitochondrial Mg2+ exporter that works together with mitochondrial importers to ensure the precise control of mitochondrial Mg2+ homeostasis. (C) 2015 Elsevier B.V. All rights reserved.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: Synthetic aperture radar (SAR) provides a powerful surveillance capability allowing the observation of target, independently from weather effects and from the day and night cycle. Unfortunately, the automatic interpretation of SAR images is often complicated and time consuming. In support of real-time vessel monitoring, a fast line-scanning detector designed for detecting ships from SAR imagery is proposed in this paper. The detector does not require any prior knowledge about ships and background observation. It uses a novel local gray-level gathering degree algorithm to detect potential targets and then a complementary filtering scheme to reject false alarms. The performance analysis over real SAR images confirms that the proposed detector works well in various circumstances with high detection rate, fast detection speed and perfect shape preservation.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: Pneumolysin is one of the major virulence factors elaborated by Streptococcus pneumoniae; this toxin is a member of the cholesterol-dependent cytolysins. Engagement of cholesterol induces the formation of a multi-subunit complex by pneumolysin that lyses host cells by forming pores on the membrane. Because pneumolysin released by bacteria which have been killed by conventional antibiotics is still active, agents capable of directly attacking the toxin are considered advantageous against antimicrobials in the treatment of S. pneumoniae infections. Here we found that the phytosterol, beta-sitosterol, effectively protects against cell lysis caused by pneumolysin. This compound interacts with the toxin at Thr459 and Leu460, two sites important for being recognized by its natural ligand, cholesterol. Similar to cholesterol, beta-sitosterol induces pneumolysin oligomerization. This compound also protects cells from damage by other cholesterol-dependent toxins. Finally, this compound protects mice against S. pneumoniae infection. Thus, beta-sitosterol is a candidate for the development of anti-virulence agents against pathogens that rely on cholesterol-dependent toxins for successful infections.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: Peroxisome proliferator-activated receptor-gamma (PPAR gamma) is a ligand-activated nuclear receptor and plays an essential role in insulin signaling. Macrophage infiltration into adipose tissue is a character of metabolic inflammation and closely related to insulin resistance in type 2 diabetes. The mechanism by which pro-inflammatory macrophages cause insulin resistance remains to be elucidated. Here we showed that coculture with macrophages significantly suppressed the transcriptional activity of PPAR gamma on its target genes in 3T3-L1 preadipocytes and diabetic primary adipocytes, depending on inducible nitric oxide synthase (iNOS). We further showed that PPAR gamma underwent S-nitrosylation in response to nitrosative stress. Mass-spectrometry and site-directed mutagenesis revealed that S-nitrosylation at cysteine 168 was responsible for the impairment of PPAR gamma function. Extended exposure to NO instigated the proteasome-dependent degradation of PPAR gamma. Consistently, in vivo evidence revealed an association of the decreased PPAR gamma protein level with increased macrophage infiltration in visceral adipose tissue (VAT) of obese diabetic db/db mice. Together, our results demonstrated that pro-inflammatory macrophages suppressed PPAR gamma activity in adipocytes via S-nitrosylation, suggesting a novel mechanism linking metabolic inflammation with insulin resistance. (C) 2015 Elsevier Inc. All rights reserved.
分类: 生物学 >> 生物物理学 >> 细胞生物学 提交时间: 2016-05-12
摘要: p53 is an important tumor suppressor and stress response mediator. Proper control of p53 level and activity is tightly associated with its function. Posttranslational modifications and the interactions with Mdm2 and Mdm4 are major mechanisms controlling p53 activity and stability. As p53 protein is short-lived and hardly detectable in unstressed situations, less is known on its basal level expression and the corresponding controlling mechanisms in vivo. In addition, it also remains obscure how p53 expression might contribute to its functional regulation. In this study, we established bacterial artificial chromosome transgenic E.coli beta-galactosidase Z gene reporter mice to monitor p53 expression in mouse tissues and identify important regulatory elements critical for the expression in vivo. We revealed preferentially high level of p53 reporter expressions in the proliferating, but not the differentiated compartments of the majority of tissues during development and tissue homeostasis. In addition, tumors as well as regenerating tissues in the p53 reporter mice also expressed high level of beta-gal. Furthermore, both the enhancer box sequence (CANNTG) in the p53 promoter and the 3' terminal untranslated region element were critical in mediating the high-level expression of the reporter. We also provided evidence that cellular myelocytomatosis oncogene was a critical player regulating p53 mRNA expression in proliferating cells and tissues. Finally, we found robust p53 activation preferentially in the proliferating compartment of mouse tissues upon DNA damage and the proliferating cells exhibited an enhanced p53 response as compared with cells in a quiescent state. Together, these results suggested a highly regulated expression pattern of p53 in the proliferating compartment controlled by both transcriptional and posttranscriptional mechanisms, and such regulated p53 expression may impose functional significance upon stress by setting up a precautionary mode in defense of cellular transformation and tumorigenesis.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: Objective: Sera of Hashimoto's thyroiditis (HT) patients are known to exhibit elevated levels of anti-thyroglobulin IgG (TgAb IgG). Therefore, TgAb IgG represents a hallmark of this debilitating autoimmune disease. The aim of our study was to investigate the differential expression of specific glycosylation patterns of TgAb IgG from HT patients and healthy blood donors. Methods: HT patients (n = 32) were divided into two subgroups, medium level group (mHT, n = 15) and high level group (hHT, n = 17), according to the serum levels of TgAb detected by electrochemiluminescence immunoassay. TgAb IgG was purified by affinity chromatography from the sera of the HT group and control group (n = 15). MALDI-QIT-TOF-MS/MS spectrometry was performed to identify the glycosylation profiles of purified TgAb IgG. Lectin microarray technology was used to compare the abundance of different glycans found on TgAb IgG between HT patients and controls, and between the mHT and hHT groups. Results: The results by MALDI-QIT-TOF-MS/MS showed that the glycosylation profiles of TgAb IgG were similar between the mHT, hHT, and control groups. Furthermore, the lectin microarray showed that compared to the control group (all P < .001), there were higher levels present of (1) mannose (detected as lectin LCA, VFA, and MNA-M); (2) terminal sialic acid (detected as SNA-I and PSA); (3) core fucose (detected as LcH); and (4) Gal(beta 1-4) GlcNAc(beta 1-2) Man glycans (detected as PHA-L) on TgAb IgG from the HT group. A similar trend was observed between the hHT and mHT group, with elevated levels of mannose, terminal sialic acid, core fucose, and Gal(beta 1-4) GlcNAc(< 12) Man glycans on TgAb IgG found in the hHT group compared with the mHT group (all P < .05). Conclusions: TgAb IgG of HT patients exhibits higher glycosylation levels than those observed for TgAb IgG of healthy controls. Our results provide new clues for exploring the role of TgAb in the pathogenesis of HT.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: Objective. We sought to use the regional homogeneity (ReHo) approach as an index in the resting-state functional MRI to investigate the gender differences of spontaneous brain activity within cerebral cortex and resting-state networks (RSNs) in young adult healthy volunteers. Methods. One hundred and twelve healthy volunteers (56 males, 56 females) participated in the resting-state fMRI scan. The ReHo mappings in the cerebral cortex and twelve RSNs of the male and female groups were compared. Results. We found statistically significant gender differences in the primary visual network (PVN) (P < 0.004, with Bonferroni correction) and left attention network (LAtN), default mode network (DMN), sensorimotor network (SMN), executive network (EN), and dorsal medial prefrontal network (DMPFC) as well (P < 0.05, uncorrected). The male group showed higher ReHo in the left precuneus, while the female group showed higher ReHo in the right middle cingulate gyrus, fusiform gyrus, left inferior parietal lobule, precentral gyrus, supramarginal gyrus, and postcentral gyrus. Conclusions. Our results suggested that men and women had regional specific differences during the resting-state. The findings may improve our understanding of the gender differences in behavior and cognition from the perspective of resting-state brain function.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: NLRP10 is a special member of NOD-like receptors (NLRs) family that lacks the leucine-rich repeats, suggesting that NLRP10 may act as an immunity regulator rather than directly receptor recognizing intracellular pathogen products. Previous studies on NLRP10 show that NLRP10 can interact with several components of NOD1 pathway thereby enhancing NOD1-mediated innate immune responses. In particular models, NLRP10 also negatively affects the activation of NLRP3 inflammasome. It has been proposed that NLRP10 oligomers interact with ASC to form a multi-protein platform for the recruitment of caspase-1 or other signaling components. Here, we show that pyrin-like domain (PYD) degradation induce the formation of NLRP10 oligomers, which present stick-shaped and circular structure. With the NLRP10 mutant G173A made by means of site-directed mutagenesis, we successfully obtain homogeneous full-length NLRP10 preparations. Corresponding gel filtration analysis and electron microscope (EM) data further proved that the PYD domain is important in protecting NLRP10 against aggregation.
分类: 生物学 >> 生物物理学 >> 细胞生物学 提交时间: 2016-05-12
摘要: Mitochondrial calcium uniporter (MCU) is a conserved Ca2+ transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress-induced cell death remains unclear. Here, we showed that ectopically expressed MCU is mitochondrial localized in both HeLa and primary cerebellar granule neurons (CGNs). Knockdown of endogenous MCU decreases mitochondrial Ca2+ uptake following histamine stimulation and attenuates cell death induced by oxidative stress in both HeLa cells and CGNs. We also found MCU interacts with VDAC1 and mediates VDAC1 overexpression-induced cell death in CGNs. This finding demonstrates that MCU-VDAC1 complex regulates mitochondrial Ca2+ uptake and oxidative stress-induced apoptosis, which might represent therapeutic targets for oxidative stress related diseases.
分类: 生物学 >> 生物物理学 >> 免疫学 提交时间: 2016-05-11
摘要: Microbiota-mediated effects on the host immune response facilitate colonization resistance against pathogens. However, it is unclear whether and how the host immune response can regulate the microbiota to mediate colonization resistance. ID2, an essential transcriptional regulator for the development of innate lymphoid cell (ILC) progenitors, remains highly expressed in differentiated ILCs with unknown function. Using conditionally deficient mice in which ID2 is deleted from differentiated ILC3s, we observed that these mutant mice exhibited greatly impaired gut colonization resistance against Citrobacter rodentium. Utilizing gnotobiotic hosts, we showed that the ID2-dependent early colonization resistance was mediated by interleukin-22 (IL-22) regulation of the microbiota. In addition to regulating development, ID2 maintained homeostasis of ILC3s and controlled IL-22 production through an aryl hydrocarbon receptor (AhR) and IL-23 receptor pathway. Thus, ILC3s can mediate immune surveillance, which constantly maintains a proper microbiota, to facilitate early colonization resistance through an ID2-dependent regulation of IL-22.